Epidemiologic support for the hypothesis that Hodgkin's disease (HD) is infectious rests upon the apparent aggregation of the disease among persons attending certain schools on Long Island, New York. However, there are several deficiencies in this study, especially the low rate of case identifiation. Nonetheless, the findings of the study are of such significance that it is urgent that it be substantiated or refuted. We have thus decided to replicate the study in Boston (with correction of some deficiencies). All persons with HD diagnosed from 1959-1973 who are residents of Greater Boston will be identified via hospitals. It will then be determined which high schools were attended by persons born from 1940-1961. The data will be analyzed both in a manner identical to that used for the Long Island study and in other ways.